Electromagnetic Waves are electric and magnetic disturbances that transfer energy from one place to another.
- Electromagnetic waves don't transfer matter.
- The energy they transfer depends on the wavelength of the waves.
- Waves that have different wavelengths have different effects.
The wavelength is the distance from one wave peak to the next wave peak along the waves.
The frequency of electromagnetic waves of a certain wavelength is the number of complete waves passing a point each second.
All electomagnetic waves travel at a speed of 300 million m/s through space or in a vacuum.
Wave speed=frequency x wavelenght
- Wave speed= metres per second
- The electromagnetic spectrum in order of increasing wave lengh is:
- Gamma and Xrays, ultraviolet, visible, infra-red, microwaves, radiowaves.
X-rays and gamma rays are absorbed by dense materials such as bone and metal, they damage living tissue when they pass through it. They both have similar wave lengths and properties
X rays are used in hospitals to take radiographs.
Gamma rays are used to:
- kill harmful bacteria in food
- to kill cancer cells
- to sterilise surgical equipment.
Each colour of the visible spectrum has a different wavelength, the wavelength increases across the…